JP2007139201A - Hot water storage type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an undershoot and overshoot in an initial period of water re-supply, in a hot water storage type water heater wherein water of high temperature and water of intermediate temperature are taken out from a hot water storage tank in supplying hot water. <P>SOLUTION: In this hot water storage type water heater comprising the hot water storage tank 1 for storing hot water, a high-temperature water supply pipe 4 for allowing the water of high temperature in the hot water storage tank 1 to flow out, an intermediate-temperature water supply pipe 5 for allowing the water of intermediate temperature in the hot water storage tank 1 to flow out, an intermediate-temperature water mixing valve 7 for mixing the high-temperature water from the high-temperature water supply pipe 4 and the intermediate-temperature water from the intermediate-temperature water supply pipe 5, and a hot water supply mixing valve 8 for mixing the hot water mixed by the intermediate-temperature water mixing valve 7 and the water supplied from a water supply pipe 3, and supplying the same from the hot water supply port 10, a check valve 31 is mounted in the intermediate-temperature water supply pipe 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot water mixing type hot water storage type hot water supply apparatus in which hot water supplied from a hot water storage tank and water supplied from a water supply pipe are mixed by a mixing valve and discharged from a hot water supply port.

  An example of the configuration of a hot and cold water storage type hot water supply apparatus is shown in FIG. Reference numeral 1 denotes a hot water storage tank for storing hot water, and water is supplied to the hot water storage tank 1 through a water supply main 2 connected to a water supply or the like. The water supplied into the hot water storage tank 1 is heated by, for example, a heat pump type heater 21 to become hot water and is stored in the hot water storage tank 1. The heater 21 is connected to the hot water storage tank 1 through a circulation path composed of an outward pipe 22 and a return pipe 23. A circulation pump 24 is interposed in the forward pipe 22.

  As for the hot water in the hot water storage tank 1, high-temperature hot water (high-temperature water) is taken out via the high-temperature water hot-water supply pipe 4, and medium-temperature hot water (medium-temperature water) is taken out via the intermediate-temperature water hot-water supply pipe 5. The hot water hot water supply pipe 4 is attached to the upper part of the hot water storage tank 1, and the intermediate hot water hot water supply pipe 5 is attached to the middle of the hot water storage tank 1 at a position lower than the hot water hot water supply pipe 4. The extracted high-temperature water and medium-temperature water are mixed by the mixing valve 7 (hereinafter, this mixing valve is referred to as “medium-temperature water mixing valve”) and flows out to the hot water supply pipe 6. The downstream side of the hot water supply pipe 6 is branched into hot water supply branch pipes 6a and 6b, and each downstream end port thereof is connected to each hot water side port of the mixing valves 8 and 9 (hereinafter, these mixing valves are referred to as “hot water mixing valves”). Has been. The downstream side of the water supply pipe 3 branched from the water supply main pipe 2 is branched into water supply branch pipes 3a and 3b, and the respective downstream end ports thereof are connected to the water side ports of the hot water mixing valves 8 and 9, respectively. Each of the intermediate temperature water mixing valve 7 and the hot water mixing valves 8 and 9 is a three-way valve capable of proportional control, and is shown as an electric three-way valve in the drawing.

  The hot water mixed by the hot water mixing valves 8 and 9 is discharged from the hot water supply ports 10 and 11 through the hot water discharge pipes 12 and 13, respectively. The hot water supply port 10 is provided, for example, in a kitchen, and the hot water supply port 11 is provided, for example, in a bath. A temperature sensor 14 for detecting the hot water temperature and a flow rate counter 15 for measuring the amount of hot water supply are provided on the hot water discharge pipe 12 from the upstream side, and a temperature sensor 16 and a flow rate counter 17 are similarly provided on the hot water discharge pipe 13. .

  The reason for taking out the medium temperature water together with the high temperature water from the hot water storage tank 1 is as follows. When reheating or the like is performed with hot water, the temperature of the hot water in the hot water storage tank 1 is decreased by heat exchange, and high temperature water is accumulated in the upper layer and intermediate temperature water is accumulated in the middle layer due to the specific gravity. This medium-temperature water causes a reduction in COP (energy consumption efficiency) of the heater 21 in the case of reboiling. Therefore, when the hot water is discharged, the medium temperature water is actively taken out from the hot water storage tank 1 together with the high temperature water, and the decrease in COP is suppressed.

  The operation of the hot water storage type hot water supply apparatus is controlled by the control device 25. As an example of feedback control of the hot water mixing valve 8, when the hot water supply port 10 is opened and hot water is detected by the flow rate counter 15, the control device 25 indicates that the hot water temperature detected by the temperature sensor 14 is the remote controller 26 or the like. The feedback of the opening degree of the hot water mixing valve 8 is controlled so that the hot water temperature is set in advance. In addition, as feedforward control, the hot water mixing valve 8 is in a state of waiting while maintaining an appropriate opening degree in preparation for the next hot water (re-hot water) after the hot water from the hot water outlet 10 is stopped. This suppresses undershoot (a phenomenon in which the hot water temperature falls below the set value) and overshoot (a phenomenon in which the hot water temperature exceeds the set value) at the initial stage of re-draining. Further, the control device 25 controls the opening degree of the intermediate hot water mixing valve 7 and the hot water supply mixing valve 9, and further, based on detection of a plurality of temperature sensors (not shown) provided in the hot water storage tank 1, etc. The heater 21 and the circulation pump 24 are also controlled.

An example of a hot and cold water storage type hot water storage apparatus similar to the above configuration is described in Patent Document 1.
JP 2003-240342 A

  By the way, in the conventional hot water storage type hot water supply apparatus, when hot water stops and enters a standby state, hot water having a predetermined temperature can be quickly supplied to the hot water supply mixing valves 8 and 9 when the hot water is discharged again. 7 is waiting at a certain opening. At this time, the high temperature water from the high temperature water hot water supply pipe 4 and the medium temperature water from the intermediate temperature water hot water supply pipe 5 cause convection in the intermediate temperature water mixing valve 7, and the middle temperature water mixing valve 7 reaches the middle of the intermediate temperature water hot water supply pipe 5. In some cases, it became hot water. Accordingly, in this case, only hot water is supplied from the intermediate hot water mixing valve 7 to the hot water mixing valves 8 and 9 at the initial stage of re-draining, and the hot water temperature at the hot water mixing valves 8 and 9 is incorrect. There was a problem that it was easy to become.

  The present invention has been made to solve such a problem, and in a hot water storage type hot water supply apparatus of a type that takes out high-temperature water and medium-temperature water from a hot water storage tank at the time of hot water discharge, An object of the present invention is to provide a hot water storage type hot water supply apparatus that can stably suppress undershoot and overshoot.

  In order to solve the above problems, the present invention provides a hot water storage tank for storing hot water, a high temperature water hot water pipe for discharging high temperature water in the hot water storage tank, and a position lower than the hot water hot water supply pipe with respect to the hot water storage tank An intermediate-temperature water hot-water pipe connected to the hot-water storage tank for flowing out the intermediate-temperature water in the hot-water storage tank; and a medium-temperature water mixing valve that mixes high-temperature water from the high-temperature water hot-water pipe and medium-temperature water from the medium-temperature water hot-water pipe; A hot water storage water heater comprising a hot water mixing valve that mixes hot water mixed by a medium temperature water mixing valve and water supplied from a water supply pipe and discharges the hot water from a hot water outlet. A hot water storage type hot water supply apparatus characterized in that a check valve is provided.

  According to this hot water storage type hot water supply apparatus, the intermediate hot water mixing valve is provided in the intermediate hot water hot water supply pipe so that hot water of a predetermined temperature can be supplied to the hot water mixing valve quickly when re-watering. Even when waiting at the opening, convection between the hot water from the hot water hot water supply pipe and the hot water from the intermediate hot water hot water pipe through the intermediate hot water mixing valve does not occur. Therefore, at the time of re-heating, in the intermediate temperature water mixing valve, the high temperature water from the high temperature water hot water supply pipe and the intermediate temperature water from the intermediate temperature water hot water supply pipe can be mixed from the beginning. The mixing condition is stabilized. Thereby, the feedforward control of the hot water supply mixing valve located on the downstream side becomes accurate, and the occurrence of undershoot and overshoot at the initial stage of re-watering can be suppressed.

  Further, the present invention sets the intermediate temperature water mixing valve set temperature in the intermediate temperature water mixing valve to a predetermined temperature higher than the hot water supply set temperature, and when the temperature of the intermediate temperature water is equal to or higher than the intermediate temperature water mixing valve set temperature, the intermediate temperature water mixing valve Waits at an opening degree that allows 100% communication with the intermediate hot water hot water pipe side, and the hot water mixing valve controls the mixing with the water from the hot water pipe with the heat source temperature as the temperature of the intermediate hot water, When the temperature of the intermediate warm water mixing valve is lower than the set temperature, the intermediate temperature water mixing valve waits while maintaining the opening at the time of the last hot water stop, and at the time of re-heating, the mixed hot water becomes the intermediate temperature water mixing valve set temperature. The hot water mixing valve is controlled so that mixing with water from the water supply pipe is controlled with the heat source temperature being set to a medium temperature water mixing valve set temperature. And the.

  According to this hot water storage type hot water supply apparatus, when the temperature of the intermediate temperature water is equal to or higher than the set temperature of the intermediate temperature water mixing valve, the intermediate temperature water mixing valve waits at an opening degree that allows 100% communication with the intermediate temperature water hot water supply pipe side. Mixing with water from the water supply pipe is controlled using the temperature of the heat source as the temperature of the medium temperature water, and when the temperature of the medium temperature water is lower than the set temperature of the medium temperature water mixing valve, the medium temperature water mixing valve maintains the opening when the last hot water supply was stopped. The hot water mixed valve is controlled so that the mixed hot water becomes the intermediate hot water mixing valve set temperature at the time of re-heating, and the hot water mixing valve uses the heat source temperature as the intermediate hot water mixing valve set temperature and the water from the water supply pipe. Therefore, the temperature of the hot water flowing from the medium temperature water mixing valve to the hot water mixing valve is stabilized regardless of the temperature of the medium temperature water, thereby stabilizing the control of the hot water mixing valve. It is capable to stabilize the hot water temperature from the mouth.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where it mixes and uses the high temperature water and medium temperature water taken out from the hot water storage tank, the undershoot and overshoot at the initial stage of re-draining hot water can be suppressed. Thereby, it becomes a hot water storage type hot water supply apparatus excellent in the hot water temperature characteristic at the initial stage of re-hot water.

  The present invention will be described with reference to FIG. 1, and description of matters that overlap with the constituent members described in the “Background Art” column will be omitted. FIG. 1 is a circuit configuration diagram of a hot water storage type hot water supply apparatus according to the present invention. FIG. 1 differs from FIG. 2 only in that a check valve 31 is provided.

  The present invention is connected to a hot water storage tank 1 for storing hot water, a high temperature water hot water supply pipe 4 for discharging high temperature water in the hot water storage tank 1, and a position lower than the high temperature water hot water supply pipe 4 with respect to the hot water storage tank 1, A medium-temperature water hot water pipe 5 that discharges medium-temperature water in the hot water storage tank 1, a medium-temperature water mixing valve 7 that mixes high-temperature water from the high-temperature water hot-water pipe 4 and medium-temperature water from the medium-temperature water hot-water pipe 5, and this medium-temperature water A hot water storage type hot water supply apparatus provided with a hot water mixing valve 8 (9) for mixing hot water mixed by the mixing valve 7 and water supplied from the water supply pipe 3 and discharging hot water from the hot water supply port 10 (11). Thus, the main feature is that the check valve 31 is provided in the intermediate temperature hot water supply pipe 5.

  A preferred control mode after providing the check valve 31 will be described. The operation of the system on the side of one hot water inlet 10 will be described below, but the same applies to the side of the hot water inlet 11.

  First, when the hot water supply port 10 that has discharged hot water is closed, the control device 25 detects the hot water supply stop of the hot water supply port 10 based on the signal from the flow rate counter 15. The control device 25 waits for the hot water mixing valve 8 at the opening when the hot water supply is stopped, that is, the opening when the control device 25 detects the hot water supply stop of the hot water supply port 10 (standby opening). Let

  Here, the intermediate temperature water mixing valve set temperature T2 (the temperature of the hot water mixed by the intermediate temperature water mixing valve 7) is set in the middle of the hot water mixing valve 8 relative to the hot water supply temperature T1 of the hot water inlet 10. It can be set as a high temperature (hot water supply set temperature T1 + α) by the amount of intervention. α is an arbitrarily set temperature value. When the temperature T3 of the medium temperature water at the medium temperature water outlet 27 of the hot water storage tank 1 is equal to or higher than the medium temperature water mixing valve set temperature T2, that is, if “T3 ≧ T2”, the medium temperature water mixing valve 7 Only the hot water hot water supply pipe 5 side needs to communicate with the hot water supply pipe 6, and the medium hot water hot water supply pipe 5 side is made to stand by at an opening degree that allows 100% communication. As hot water can be used 100%, it is efficient. The difference (T3-T2) is absorbed by feedforward control of the hot water mixing valve 8 so as to increase the mixing ratio of water from the water supply branch pipe 3a. Note that the temperature T3 of the medium temperature water at the medium temperature water outlet 27 is detected by a temperature sensor (not shown).

  Further, when the temperature T3 of the intermediate temperature water is lower than the set temperature T2 of the intermediate temperature water, that is, when “T3 <T2” is established, the intermediate temperature water mixing valve 7 is turned on when the hot water supply port 10 is closed (previous time). Maintaining the opening of the hot water supply stop) and waiting. In the intermediate temperature water mixing valve 7 in this standby state, the high temperature water hot water supply pipe 4 side and the medium temperature water hot water supply pipe 5 side are in communication with each other. When the hot water outlet 10 is re-drained, the opening of the hot water mixing valve 7 is controlled so that the mixed hot water becomes the hot water mixing valve set temperature T2.

  In the case of the former “T3 ≧ T2”, the parameter for feedforward control of the hot water mixing valve 8 is only the temperature T3 of the intermediate temperature water at the intermediate temperature water outlet 27. In other words, the hot water mixing valve 8 uses the heat source temperature as the temperature T3 of the intermediate temperature water and the mixing with the water from the water supply pipe 3 is controlled, so that the temperature of the hot water outlet 10 with respect to the hot water set temperature T1 is accurate, Undershoot and overshoot hardly occur at the beginning of the hot water.

  However, in the latter case of “T3 <T2”, if there is no check valve 31 as shown in FIG. In the case of “T3 <T2”, the parameter for feedforward control of the hot water mixing valve 8 is that the high temperature water and the medium temperature water are mixed by the medium temperature water mixing valve 7 and the medium temperature water mixing valve set temperature T2 Become. That is, the hot water supply mixing valve 8 is controlled to be mixed with water from the water supply pipe 3 with the heat source temperature set to the intermediate temperature water mixing valve set temperature T2. At this time, if the check valve 31 is not provided, due to the specific gravity, the hot water from the hot water hot water supply pipe 4 is convected through the intermediate hot water mixing valve 7 to the intermediate hot water hot water supply pipe 5 side, so that the intermediate hot water mixing is performed. There arises a problem that the valve set temperature T2 is not stable. As a result, the feedforward control of the hot water supply mixing valve 8 tends to be inaccurate, and undershoot and overshoot are likely to occur at the initial stage of re-watering.

  On the other hand, in the present invention, since the check valve 31 is provided in the intermediate temperature hot water supply pipe 5, the inflow of high temperature water into the intermediate temperature hot water supply pipe 5 is prevented. Thereby, the mixing condition of the high temperature water and the medium temperature water by the medium temperature water mixing valve 7 is stabilized, and the medium temperature water mixing valve set temperature T2 is stabilized. Therefore, the feedforward control of the hot water supply mixing valve 8 located on the downstream side becomes accurate, and the occurrence of undershoot and overshoot at the initial stage of re-watering is suppressed. Note that the check valve 31 is preferably provided in the vicinity of the medium temperature water mixing valve 7 in order to effectively prevent the inflow of high temperature water.

  As described above, after the check valve 31 is provided in the intermediate warm water hot water supply pipe 5, the intermediate warm water mixing valve set temperature T2 in the intermediate warm water mixing valve 7 is set higher than the hot water supply set temperature T1 by a predetermined temperature (α). When the temperature T3 of the intermediate temperature water is equal to or higher than the set temperature T2 of the intermediate temperature water mixing valve, the intermediate temperature water mixing valve 7 waits at an opening degree that allows 100% communication with the intermediate temperature water supply pipe 5 side, and the hot water supply mixing valve 8 sets the heat source temperature to the middle. Mixing with water from the water supply pipe 3 is controlled as the temperature T3 of the hot water, and when the temperature T3 of the intermediate temperature water is lower than the set temperature T2 of the intermediate temperature water mixing valve, the intermediate temperature water mixing valve 7 has the opening at the time of the last hot water stop. While maintaining and waiting, when the hot water is discharged from the hot water supply port 10, the mixed hot water is controlled so as to become the intermediate hot water mixing valve set temperature T 2, and the hot water mixing valve 8 controls the heat source temperature to the intermediate hot water mixing. If the mixing with the water from the water supply pipe 3 is controlled as the set temperature T2, the medium temperature water can be used efficiently, and the medium temperature water mixing valve 7 to the hot water mixing valve 8 can be used regardless of the temperature of the medium temperature water. Since the temperature of the hot water flowing in the water can be stabilized, the control by the hot water mixing valve 8 is stabilized, and the temperature of the hot water discharged from the hot water outlet 10 can be stabilized.

  The preferred embodiments of the present invention have been described above. In the embodiment, the case where two hot water mixing valves 8 and 9 are provided in parallel between the hot water supply pipe 6 and the water supply pipe 3 has been described. However, the case where the hot water mixing valves 8 and 9 are provided as a single unit or three or more hot water mixing valves are provided in parallel. It may be the case.

It is a circuit block diagram of the hot water storage type hot water supply apparatus which concerns on this invention. It is a circuit block diagram of the conventional hot water storage type hot water supply apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 3 Water supply pipe 4 High temperature water hot water supply pipe 5 Medium hot water hot water supply pipe 6 Hot water supply pipe 7 Medium hot water mixing valve 8, 9 Hot water mixing valve 10, 11 Hot water inlet 31 Check valve

Claims (2)

A hot water storage tank for storing hot water,
A hot water hot water pipe that drains the hot water in the hot water storage tank,
A medium hot water hot water pipe connected to the hot water storage tank at a position lower than the high temperature water hot water pipe, and allowing the medium temperature water in the hot water tank to flow out;
A medium temperature water mixing valve that mixes high temperature water from the high temperature water hot water pipe and medium temperature water from the medium temperature water hot water pipe;
A hot water mixing valve that mixes the hot water mixed by the medium hot water mixing valve and the water supplied from the water supply pipe to discharge the hot water from the hot water outlet;
A hot water storage device equipped with
A hot water storage type hot water supply apparatus, wherein a check valve is provided in the intermediate temperature hot water supply pipe. The medium temperature water mixing valve set temperature in the medium temperature water mixing valve is set higher than the hot water supply temperature by a predetermined temperature
When the temperature of the intermediate temperature water is equal to or higher than the set temperature of the intermediate temperature water mixing valve, the intermediate temperature water mixing valve waits at an opening degree that allows 100% communication with the intermediate temperature hot water supply pipe side, and the hot water supply mixing valve sets the heat source temperature to the intermediate temperature water. Mixing with water from the water supply pipe is controlled as temperature,
When the temperature of the medium-temperature water is lower than the set temperature of the medium-temperature water mixing valve, the medium-temperature water mixing valve stands by while maintaining the opening at the time of the last hot water stop, and at the time of re-watering, the mixed warm water is mixed with the medium-temperature water It is controlled so that it may become valve setting temperature, and mixing with the water from the said water supply pipe is controlled by making the said hot water mixing valve into the hot water mixing valve setting temperature as the heat source temperature. Hot water storage water heater.

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